Heat motor



A. E. BAAK Aug. 8, 1944.

HEAT IOTOR Original Filed Jan. 2, 1941 Fig. 2.

INVENTOR. Al'kmr'i" E. PacLcLL Afl'orney' Fig. 3

Patented Aug. 8, 1944 Original application January 2, 1941, Serial No. 372,283. Divided and this application October 25, 1941. Serial No. 416.511

1: Claims. (01. 172-126) This invention is concerned with a heat actuated motor, particularly a motor adapted to produce rotary motion.

The principal object of the invention is'to provide an improved heat actuated device for producing rotary motion utilizing a minimum of parts and occupying a minimum of space.

Another object is to provide an improved heat motor comprising a rotary element actuated by expansible .and contractlble heat responsive means located within the element.

Another object is to provide an improved heat motor for a timer or the like having an expansible and contractible heat responsive element so arranged that the element rotates a member about a shaft both when the element cools and when it heats.

Another object of the invention is to provide improved adjusting means associated ,with the heat motor for adjusting the speed at which the rotary element isdriv'en. I

Numerous other objects of the invention and many of its advantages will become apparent from the following detailed description and annexed drawing, wherein Figure 1 is a diagrammatic view of the preferred form of my invention embodied in a system wherein the heat motor drives a timing by the heat motor,

Figure 3 is a view of a modified form of heat motor. This application is a division of my previously filed application Serial No. 372,783, flied January 2, 1941, now Patent Number 2,326,002, August 3, 1943.

Referring to Figure l of the drawing, the heat motor is designated generally by th numeral II, the parts being mounted on a base or panel ll. Carried on the base Ii is an arbor l2 and on the arbor is a cylindrical "Bakeli member having a flange l3. Rotatably supported on th Bakelite" member and the arbor I2 is a member ll having an integral downwardly extending arm II. The member I has an integral upwardly extending arm l6. Numeral i1 designates a normally fixed arm member pivotally carried on the arbor I! but having a screw it attached thereto which extends through an arcuate slot II in the base or panel ,I I, which screw carries a nut on the opposite side of the base for securing the arm I! in position. The arm I! has an ear 20 and between this ear and the arm I! is secured a bimetal element 2| oi the double helix type as shown and described in detail in the patent of Parsons, No. 2,121,259. The bimetal element 2| is formed of a strip of bimetal which is first coiled into a spiral and this spiral is then coiled into a second spiral as shown. This arrangement of the bimetal makes it possible to have a relatively large amount of bimetal arranged in a small and compact space, the amount of bimetal being suiliclent to provide a relatively large amount of movement when th bimetal expands and contracts in response to temperature changes. This particular arrangement of biwhich forms a pawl. Numeral 28 designates a cylindrical, more or less cup-shaped member having a downwardly extending skirt portion 21 as shown in the upper portion of Fig. 1. The interior of the skirt portion is grooved or serrated as may be seen in Fig. 1 and the finger 25 which forms a pawl is adapted to engage the serration. The member 2! is rigidly fastened to a shaft 28, the lower end of which extends into a hole 29 in the arbor l2 so that the member" is rotatable with respect 'to the arbor, the various parts of the heat motor being enclosed in the skirt portion of the member 2'. A cover may be provided so as to enclose the elements of the heat motor including the cup-shaped member 28, the cover fitting down on the base II and the upper end of the shaft 28 extending through the cover as shown in the upper portion of Fig. 1. The member 28 has a portion ll of relatively small diam- ,eter adjacent its upper face. The upper face of the member 2! is shaped so as to form a cam surface, the plan view of the cam surface being shown in Fig. 2. The cam surface comprises four gradually rising dwells as shown which are equally spaced angulariy near the outer edges of the face of the member 2|.

The finger 2| is flexible and when the arm II is moved to the left in a manner which will be presently described the linger 25 engages the serrations on the inner surface of the skirt 21 moving the cam member 20 in a counterclocb wise direction. When the arm II is moved to the right the finger 2! slides over the serrations without moving the member 2|.

Numeral I! designates an angular arm pivoted on a fixed pivot 36 and having a slotted portion, the slot engagin a pin 28 carried by a portion of the member I. At the end of the arm 35, is a linger 32 corresponding to the finger 25, this finger also forming a pawl engaging the serrations on the inner surface of the skirt 2! of member 25. As will presently be described, the arm 35 may be moved to the left so as to rotate the member 26 in a counterclockwise direction in the same manner as it is rotated by the pawl 25.

Numeral 40 designates a flexible blade, the lower end of which is attached to the member l4 and the upper end of which carries a contact 4|, the upper end being slightly spaced from the arm [6. Attached to the upper end of the blade 40 is an angular member 42 which extends through an opening in arm l and which has a downwardly extending projection adapted to engage the arm l6 and limit the extent to which the blade 43 can be flexed away from the arm IS. Numeral 43 designates a contact carried at the end of a contact screw 44 which extends through a bracket member 45 which is suitably secured to the panel or base II by rivets or the like as shown. The cntact screw 44 is disposed between the legs oi a permanent magnet 45 which is attached to the bracket 45 by means of a clamp 41 and a screw 45 Member 42 forms an armature and when it is brought to a position adjacent the legs of the magnet 46 it is attracted by the field of the magnet and contacts 4| and 43 are brought together with a snap action, the blade 40 flexing away from the arm l8 which is not affected by the snap action.

Electric current for the expansible and contractible element 2| is supplied from a step down transformer 56 having a primary winding 5| and a secondary winding 52, the primary winding having a greater number of turns.

With the {parts of the heat motor in the position shown in Fig. l, the element 2| is cold and is therefore in its contracted position, it being understood thatas the element 2! contracts the arm ii of member l4 and of course the arm l5, are moved a clockwise direction. When member l4 moves in a clockwise direction, by reason of the engagement of pin 38 in the slot in portion 37 of arm 35 the arm 35 is moved in a counterclockwise direction. Thus, during the time that element 2| is contracting the pawl 39 is moving the cam member 26 in a counterclockwise direction while the pawl is sliding over the serration on the interior of the skirt 21. With the parts as shown in Fig. l, the cooling cycle has just been completed and contacts 4| and 43 have just been snapped into engagement. Engagement of these contacts completes a circuit for the primary 5| of transformer 50 as follows: from line conductor 55 through a wire 56, bracket 45, contact screw 44, contacts 43 and 4|, blade 40, member l4, arm I5, wire 51, primary 5|, and wire 58 back to a line conductor 59, line conductors 55 and 59 being connected to any suitable source of power not shown. Completion of this circuit energizes the transformer and current now flows in a circuit extending through the element 2| and through the secondary of the transformer, this circuit being as follows: from the secondary 52, through a wire 60, wire 57, element 2|, ear 20 and arm IT and wire 6| back to secondary 52. Energization of this circuit causes heating of the element 2| which causes it to expand longitudinally of its axis thereby rotating the arms l5 and IS in a counterclockwise direction about the arbor I2. The pawl engages the serrations on the inner surface of the skirt 21 of member 26 rotating it in a counterclockwise direction. counterclockwise movement of member I4 now rotates the arm in a clockwise direction about its pivot so that this arm moves towards the arm It with the pawl 39 sliding over the serrations on the inner surfaces of the skirt 21. The contacts 4| and 43 stay in engagement with each other until the arm 5 engages the downwardly extending lprojection of member 42 and when this occurs, further leftward movement of arm l5 pulls armature 42 away from magnet 46, thus moving the flexible blade 40 to the left so as to disengage the contacts 4| and 43 with a snap action and interrupt the circuit of transformer 50. When the circuit of the the transformer 50 is thus interrupted winding 52 is de-energized and heating of element 2| discontinues and it begins to cool and contract. As it contracts, member I4 is now rotated in a clockwise direction and pawl 25 now slides over the serrations on the inner surface of skirt 21 while the arm 35 is now rotated in a counterclockwise direction, arms 35 and I5 moving away from each other with pawl 39 engaging the errations on the inner surface of skirt 2! and rotating the member 25 again in a counter clockwise direction. The arms 35 and I5 continue moving away from each other until arma ture 42 approaches magnet 45 sufilciently close that contact 4| is again snapped into engagement with contact 43 with the parts again in the position shown in Fig. 1 wherein the circuit of transformer 50 is completed. It is to be noted that the flexible blade 40, because of its operation as a resilient support for contact 4|, provides some freedom of relative movement between arm l5 and contact 4|, that is, lost motion, so that considerable movement of arm I6 is required to affect opening and closing of contacts 4| and 43. By reason of the flexible blade, 40, arms l5 and 35 can move with a smooth back and forth motion inasmuch as they are free from the effects of the magnetic snap action with which contact 4| is operated.

From the foregoing, it is to be seen that the arms l6 and 35 alternately move toward and away from each other so a to walk around the inner surface of the member 21 so as to rotate it substantially uniform by and continuously in a counterclockwise direction.

By loosening the screw l5 which extends through slot l9, the position of arm I! may be adjusted and such an adjustment of course adjusts the position of element 2| and the actuator arms l6 and 35. If arm I! is adjusted to the right it is to be seen that the arm I5 is adjusted in a counterclockwise direction bringing it closer to the downwardly extending projection of member 42 so that a smaller amount of lengthening of the element 2| is required to cause arm IE to engage the downwardly extending projection of member 42 for opening the contacts. On the other hand, if the arm H is adjusted to the left arm I5 is brought closer to the armature portion of member 42 and consequently greater lengthening of element 2| is required to cause opening of the contacts and subsequent cooling of the element 2|. In other words, the length of the step" taken by the arms or rather legs I5 and 35 is adjusted by adjusting the position of arm Thus by adjusting the position of arm H the length 0f time required for the member 25 to make one complete revolution may be adjusted. Arm I1 is normally so adjusted that the member 25- makes one complete revolution per hour.

While the heat motor of my invention may have many different applications where it is desirable to produce rotary motion, in the present instance I have used it as a part of a timing mechanism which a men to intermittently operate a fuel feeding device which in this instance is an automatic stoker. The stoker is generally designated by the numeral Cl and it is controlled through a relay designated by the numeral u, the relay so comprising a winding 11 having an armature/amociated therewith which is attached to a movable switch blade having.

tors 14 and II connected to any suitable-source of power, not shown.

The relay ll may be energized by contacting means actuated by the cam member 20 driven by the heat motor. Numeral 16 designates a contact bracket carryin a contact 11 and numeral 1| designates a second contact bracket carrying a contact cooperable with the contact 11. Numeral II designates a pivoted arm member carry- -ing-at its right end a portion 0| forming a cam follower which rides on the cam surface of the member II. The cam follower portion II has an upwardly extending portion which engages the contact bracket 18. The bracket 10 normally en ages a manually adjustable eccentric or cam 02 and by adjusting the eccentric I! the position of bracket 16 and contact 11 relative to contact 10 may be adjusted.

As the cam member .26 rotates in a counterclockwise direction, the cam follower member ll rises up on the dwells upon the face of the cam member, and as it rises the bracket member 10 and contact 10 are lifted until contact 10 engages contact 11, this occurring at a point on any one of the dwells depending upon the adjustment of the blade 03 is moved out of engagement with the contact 04. When the blade 03 engages contact 04, a circuit for winding 01 is completed as follows; from secondary 18 through a wire ll,

bracket member 18. When contacts 11 and 10 are brought into engagement a circuit for energizing the winding 61 of relay .6 is completed as follows: from secondary 1! through wire OI. bracket 10. contacts 11 and 10, bracket 10, wire 00, wire I1, winding 01 and wire 08. back to secondary II. When winding 01 is energized, contacts 09 and 10 are brought into engagement completing a circuit for the motor of the automatic stoker as follows: from line conductor through wire 0!.

the motor of the stoker, wire 00, switch blade I,

structed as shown, the contacts 11 and 1! are brought into engagement four times during each revolution of the cam member. A Of course any number of dwells could. be provided and thus any number of intermittent operations of the stoker during one cycle or revolution of the commember could be provided for. As mentioned above, the duration of each intermittent operation is determined by adjusting the point on the dwell at which the contacts are brought into engagement, and this is determined by adjustment of the position of bracket 16 by means of the manually adjustable eccentric 02.

The relay is may also be energized by a thermostat responsive to the temperature of a space,

contact 04, blade 03, element 92, wire 0, wire 01. winding 1, and wire 00 back to secondary 18. The relay 6| will remain energized in response to the thermostat for operating the stoker as long a: blade 00 remains in engagement with contact I From the foregoing, it is to be seen that the heat motor of my invention provides for continuous uniform rotary motion of the cam member whereby the fuel feeding device is intermittently operated at periodic intervals. As already mentioned, the heat motor of my invention may be used in many other capacities, in'

fact, wherever uniform rotary motion is requh ed.

In Figure 3 of the drawing, I have shown a slightly, modified form of heat motor for driving the timing mechanism. In Figure 3 the heat motor is mounted on a panel II the same as Figure 1 and the rotary member 2C is the same as, that of Figure 1. In the present embodiment there are two 'bimetal elements I00 and Iii which are rigidly mounted in the position shown. being attached to brackets I02 and 103 respectively. A heating element I04 is disposed within insulating material Ill and is carried on the bimetal element I00. and one end of the heating element is connected to the element I00 while the other end is connected to the source of power. At its upper end the element carries an arm or finger I00 which forms a pawl engaging the serrationson the inner surface of the skirt of member 28. At its upper end the element i0l carries a similar finger I01 forming a pawl also engaging the inner surface of the skirt of member 26. Numeral I00 designates a contact carried at the upper end of element I00 and numeral I00 designates a contact carried at the upper end of element i0i. H0 is a permanent magnet. The circuit for heating element I04 extends through the heating element, part of the bimetal element I00, the contacts I00? I00, the bimetalelement I01 and the bracket ill! to which theother side of the circuit from the power source is connected. When the heating element I00 is energized, to heat the bimetal element, the element I00 warps to the left and the element l0l warps to the right. When the elements cool they warp toward each other so as to bring the contacts I00 and I into engagement.

With the parts in the position shown, the heat ing element I04. has been deenergized'so as to 0 allow the elements I00 and IN to cool so that they have warped toward each other bringing the contacts lll and I09 together the contacts snapping together when the end of element I00 is brought into the field of magnet H0. A circuit for the heating element is now completed as described above. The heating element I04 being insulated,,as long as it is energized its temperature rises as the heat therein accumulates.

the air of which heated by means of the plant The heat causes the bimetal elements I and iii to warp away from each other, contacts I" and I! snapping apart when the tension in the bimetal elements overcomes the attraction oi the magnet and element I00 causing pawl I06 to rotate the member 28 in a counterclockwise direction in the same manner as this member is rotated in the previous embodiment. The upper end of element ill warps to the right, with the pawl i8! sliding over the serrations on the inner surface of the member 2!. The heat which accumulates in the heater during the time it is energized causes the bimetal elements to continue to warp to some extent after the contacts are opened. When the accumulated heat has been sufliciently dissipated so as to permit the bimetal elements to begin to cool, they warp toward each other with the pawl I01 now rotating the member 26 in a counterclockwise direction and the pawl I05 sliding over the serrations. When the bimetal elements have cooled sufliciently the parts again assume the position shown in Figure 3 and the cycle is repeated. It is to be seen therefore that the arms or pawls I06 and I0! walk around the inner surface of the skirt of member 26 similarly to the operation of the previous embodiment.

The forms of my invention which I have disclosed are representative of manners in which its principles may be applied. There are other forms that it may take and various changes and modifications may be made by those skilled in the art which fall within the spirit and scope of the invention. The invention therefore is to be limited not by my disclosure but only by the claims appended hereto.

I claim as my invention:

1. A heat motor comprising in combination, a movable element, actuating means for the element comprising an arm having a pawl adapted to engage said element, a second arm having a pawl adapted to engage said element, heat responsive means for actuating said arms, a single heater for periodically heating said heat responsive means so that it alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arms so as to cause one pawl to move the element in a given direction by reason of the expansion of the heatresponsive means and to cause the other pawl to move the element in said given direction by reason of the contraction of the heat responsive means.

2. A heat motor comprising in combination, a rotary cylindrical element, actuating means for the element comprising an arm having a pawl adapted to engage said element, a second arm having a pawl adapted to engage said element, heat responsive means for actuating said arms, a single heater for periodically heating said heat responsive means so that it alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arms so as to cause one pawl to move the element in a given direction by reason of the expansion of the heat responsive means and to cause the other pawl to move the element .in said given direction by reason of the contraction of the heatresponsive means, said arms being arranged within said rotary cylindrical element.

3. A heat motor comprising in combination, a rotary element, actuating means for the element comprising an arm havinga pawl adapted to engage said element, a second arm having a pawl adapted to engage said element, heat responsive means for actuating said arms, said heat responsive means comprising a bimetal element of the double helix type, means whereby said heat responsive means alternately heats and cools so as to cause it to' expand and contract, and means whereby said heat responsive means actuates said arms so as to cause one pawl to move the element in a given direction when the heat responsive means expands and to cause the other pawl to move the element in said given direction when the heat responsive means contracts, said rotary element being relatively small and said actuating means including the bimetal element being located within the rotary element, the element and actuating arms forming a sumciently compact device to permit such location but the element by reason of its double-helix formation being capable of producing suflicient motion of the rotary element.

4. A heat motor comprising in combination, a rotary cylindrical element having an annular wall, actuating means for the element comprising an arm having a pawl adapted to engage the interior of said annular wall, heat responsive means for actuating said arm, means whereby said heat responsive means alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arm so as to cause said pawl to rotate said element, said actuating means being arranged within the rotary cylindrical element.

5. A heat motor comprising in combination, a movable element, actuating means for the element comprising an arm having a pawl adapted to engage said element, heat responsive means for actuating said arm, means whereby said heat responsive means alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arm so as to cause said pawl to move said element, said third means comprising a flexible blade attached to said arm and having one end relatively free to move, a contact carried near said end of the blade, means whereby snap movement is imparted to said contact, said flexible blade permitting snap movement of the contact without corresponding movement of the arm, and

switch means including sa d contact controlling the heating of said heat responsive means.

6. A heat motor comprising in combination, a rotary cylindrical element having an annular wall, actuating means for the element comprising an armhaving a pawl adapted to engage the interior of said annular wall, heat responsive means for actuating said arm, means whereby said heat responsive means alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arm so as to cause said pawl to rotate said element, said actuating means being arranged within the rotary cylindrical element, and said rotary element being relatively freely rotatable in one direction.

'7. In apparatus of the character described, in combination, a movable member, actuating means comprising an expansible and contractible heat responsive element, an arm movable by the element having means forming a pawl engaging the member for rotating it, contacting means controlling the heating of said element, said contacting means being operable by said element to cause it to alternately heat and cool, and means whereby a predetermined amount of expansion or contraction of the element is required to operate said contacts, said amount of expansion or contraction oi the element imparting a predetermined amount of movement to the movable member, and means for adjusting the posi; tion of the element whereby a diflerent amount of expansion or contraction is required to operate the contacts and the consequent movement imparted to the movable member is different so as to thereby vary its speed of movement.

8. A heat motor comprising in combination, a movable element, actuating means for the element comprising an arm having a pawl adapted to engage said element, a second arm having a pawl adapted to engage said element, heat responsive means for actuating said arms, means whereby said heat responsive means alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arms so as to cause one pawl to move the element in a given direction when the heat responsive means expands and to cause theother pawl to move the element in said given direction when the heat responsive means contracts, said heat responsive means comprising a bimetal element associated with each of said arms, and said means for causing alternate heating and cooling of the heat responsive means including an electrical heater disposed adjacent both bimetal elements so as to simultaneously heat both elements and allow both elements to cool.

9. A heat motor comprising in combination, a movable element, actuating means for the element comprising an arm having a pawl adapted ing means between said thermosensitive means and said movable element eflective to move said element in said given direction by reason of the movement of said thermosensitive means in the opposite direction when it is cooling.

11. A heat motor comprising, in combination, a movable element, thermosensitive means, a single electric heater for heating said therrno- I sensitive means, means including contacts posito engage said element, a second arm having a pawl adapted to engage said element, heat responsive means for actuating said arms, means whereby said heat responsive means alternately heats and cools so as to cause it to expand and contract, and means whereby said heat responsive means actuates said arms so as to cause one pawl to move the element in a given direction when the heat responsive means expands and to cause the other pawl to move the element in said given direction when the heat responsive means contracts, said heat responsive means comprising a bimetal element associated with each of said arms, and said means for causing alternate heating and cooling of the heat responsive means including an electrical heater, said heater being arranged between the bimetal elements, and the elements being so constructed and arranged as to alternately warp toward and away irom each other.

10. A heat motor comprising, in combination, a movable element, thermosensitive means, means for alternately heating said thermosensitive means and allowing it to cool, a first connecting means between said thermosensitive means and saidmovable element eii'ective to move said element in a given direction by reason of the movement or said thermosensitive means when it is being heated, and a second connecttioned by said thermosensitive means for pcriodically interrupting the energization of said heater so as to allow said thermosensitive means to cool, a first connecting means between said thermosensitive means and said movable element eflfective to move said element in a given direction by reason of the movement of said thermosensitive means when it is being heated, and a second connecting means between said thermosensitive means and said movable element eifective to move said element in said given direction by reason of the movement of said thermosensitive means in the opposite direction when it is cooling.

12. A heat motor comprising, in combination,

a movable element, a thermosensitive element, a single electric heater for heating said thermosensitive element, means for periodically energizin and deenergizing said heater to cause said thermosensitive element to be alternately heated and cooled, a pivoted connecting arm between said movable element and said thermosensitive element, said arm being connected to said thermosensitive element so as to be moved in one direction when said thermosensitive element expands'upon heating and in the opposite direction when said thermosensitive element contracts upon cooling, and a second arm pivotally mounted on a fixed support and pivotally connected to said first named arm so as to move in a direction opposite to that in which said second named arm is moved, said first and second arms each having one-way connections with said movable element so that each is effective to move said element in the same direction, one

of said arms moving said movable element as a result of said thermosensitive element heating and the other moving said movable element as a result of said thermosensitive element cooling.

13. In apparatus 01' the character described, in combination, means comprising a rotary cylindrical element adapted to rotate about a pivot, said. element having an annular wall, means including a member rotatable about the pivot and engageable with the annular wall of said element for rotating the element in one direction, means for oscillating said member to rotate the element, said last means comprising a single heat responsive expansible and contractible device adapted to alternately expand and contract, electrical means including contacts for causing said device to alternately heat and cool, and means whereby said contacts are operated with a snap action by said device.

- ALBERT E. BAAK. 

